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Joel Ullom (Fed)

Dr. Joel Ullom leads the NIST Quantum Sensors Division. He is also a Lecturer in the Department of Physics at the University of Colorado Boulder. Dr. Ullom has worked in the fields of low temperature sensors, quantum electronics, and cryogenic systems since 1994. During this time, he has done research to understand and improve the performance of superconducting transition-edge sensors. He has also worked to develop different types of refrigerators including microcoolers based on quantum tunneling and macrocoolers that reduce the need for liquid cryogens. Dr. Ullom has developed and disseminated a variety of instruments based on multiplexed arrays of cryogenic sensors.

Research Interests

  • cryogenic sensors
  • multiplexed readout techniques
  • advanced cryogenics
  • radiation detection
  • applications of cryogenic sensors in materials analysis, astrophysics, cosmology, fundamental parameters, and quantum information science

Awards

Publications

A study of the position-dependent response of thermal kinetic inductance detectors through the use of cryogenic beam steering

Author(s)
Ian Fogarty Florang, Jonathan Dean, Joseph Fowler, Tom-Erik Haugen, Shannon Hoogerheide, Daniel Jardin, Hans Mumm, Nathan Nakamura, Matthew Natale, Galen O'Neil, Nathan Ortiz, Jeremy Paster, Thomas Rao, Avirup Roy, Daniel Swetz, Joel Ullom, Michael Vissers, Paul Szypryt
There are a number of considerations when designing a low-temperature detector for the best possible energy resolution. One that has been particularly...

Prospects of kinetic inductance current sensors for multiplexed microcalorimeter readout

Author(s)
Galen O'Neil, Simon Bandler, Ian Fogarty Florang, John Mates, Daniel Swetz, Paul Szypryt, Thomas Stevenson, Leaf Swordy, Joel Ullom, Michael Vissers, Jordan Wheeler, Wonsik Yoon
Superconducting microcalorimeter arrays with hun- dreds to thousands of pixels are enabling new measurements and capabilities in exotic atom spectroscopy, x-ray...

Patents (2018-Present)

Compact Low-power Cryo-Cooling Systems For Superconducting Elements

NIST Inventors
Joel Ullom and Vincent Kotsubo
A compact, low power cryo-cooler for cryogenic systems capable of cooling gas to at least as low as 2.5 K. The cryo-cooler has a room temperature compressor followed by filtration. Within the cryostat, four counterflow heat exchangers precool the incoming high-pressure gas using the outflowing low
X-Ray Spectrometer

X-Ray Spectrometer

NIST Inventors
Kevin L. Silverman , Carl D. Reintsema , Luis Miaja Avila , Daniel Swetz , W.Bertrand (Randy) Doriese , Dan Schmidt , Bradley Alpert , Joseph Fowler , Joel Ullom and Ralph Jimenez
This invention includes: an x-ray plasma source that produces primary x-rays; an x-ray optic that transmits and focuses the primary x-ray onto a sample jet from which fluorescence x-ray are emitted; and a microcalorimeter array detector that measures the energy of the incoming fluorescence x-rays
Created October 9, 2019, Updated October 23, 2023
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